ZigBee网络测试与验证平台的设计与实现

本文的目的是为了测试采用ZigBee协议开发的设备或者产品是否符合ZigBee协议标准,从而达到实现之间的一致性与互通性。为此,设计了一个ZigBee网络测试与验证平台,通过对接入ZigBee网络的测试节点的属性数据检测,来完成ZigBee协议的测试工作。     

ZigBee网络测试与验证平台的设计与实现

本文的目的是为了测试采用ZigBee协议开发的设备或者产品是否符合ZigBee协议标准,从而达到实现之间的一致性与互通性。为此,设计了一个ZigBee网络测试与验证平台,通过对接入ZigBee网络的测试节点的属性数据检测,来完成ZigBee协议的测试工作。     

基于ZigBee技术的无线电能抄表网络节点的设计

ZigBee无线网络技术具有低功耗、低成本和短延时等优势,是目前世界上发展最快,市场前景最广阔的新技术之一。本文针对ZigBee技术特点,在ZigBee协议基础之上,采用TI公司ZigBee解决方案的高集成度、高性能SOC片上系统芯片CC2430作为控制器和无线收发器,电能表的设计采用电能计量芯片ATT7022B,设计了一种基于ZigBee技术的无线电能抄表网络节点的硬件系统方案,并对网络节点与协调器之间的无线收发进行了实际验证,协调器可以对节点进行无线抄表。结果表明:电能计量和ZigBee的点对点无线传输的正确性和可靠性。     

ZigBee节点无线定位技术在协作路由中的工作机制

新一代无线通信技术ZigBee协议具有低功耗、低成本和灵活组网等特点。系统分析ZigBee协议的网络层、路由原理,介绍了ZigBee定位原理及系统,包括定位机制,定位算法。将定位技术与路由协议有机的融合,分析定位系统在路由协议中的工作机制,对ZigBee无线定位系统的工作方式进行进一步了解。     

基于ZigBee无线通信网络的指纹考勤网络设计

本文阐述了使用ZigBee模块和指纹识别模块设计基于ZigBee无线通信网络的指纹考勤网络。指纹模块和ZigBee终端通过UART连接,使用ZigBee终端实现对指纹识别模块的控制。ZigBee网络程序是基于TI的ZigBee2006协议栈zstack开发的,实现协调器与终端间的无线数据传输。通过上位机下载指纹模板和按键的操作,实现多点人员指纹考勤：     

ZigBee路由协议分析与性能评估

在分析了ZigBee网络层各项关键技术的基础上,深入研究了ZigBee路由协议,并通过网络仿真器NS-2对其性能进行了仿真,仿真结果显示采用Cluster-Tree和AODVjr（Ad-hoc On-Demand distance Vector junior routing）相结合的ZigBee路由协议在ZigBee网络中具有较好的性能。     

ZigBee无线通信技术及其工业应用

目前,ZigBee技术已被视为无线控制网络领域最有前景的技术之一。该文介绍了详细ZigBee技术的概念、特点和开发平台,在此基础上讲解了ZigBee协议栈以及常用的几种短距离通信协议的比较。最后给出了ZigBee技术在工业领域中的典型应用。     

ZigBee在加油站管理系统中的应用

ZigBee是一种专为低成本、低速率和低功耗传感器控制网络设计的无线网络协议.本文介绍基于IEEE802.15.4的无线网络协议ZigBee的主要特征,利用ARM微处理器LPC210x和Chipcon公司的CC2420实现基于ZigBee的无线网络应用,并给出该无线传感器网络在加油站管理系统中的应用.     

移动节点在ZigBee网络中路由无缝切换的改进

ZigBee是一种新兴的无线通信技术,广泛用于自动化、远程监控等领域.由于ZigBee网络中静态路由节点与移动终端节点通信延迟严重,限制了ZigBee的应用,针对此问题提出一种改进的方案.首先简介ZigBee协议栈以及ZigBee网络层,分析现有的Z-AODV协议,并在此基础上提出移动节点快速路由的机制,从而减少通信延迟,实现移动终端节点在静态路由间的平滑无缝切换.     

基于EPA标准的ZigBee网络构建方法的研究

随着以太网技术的迅速发展,实时无线以太网已成为工业控制领域研究的热点;介绍和分析了Ethernet for plant automation(EPA)标准和ZigBee的技术要点,重点分析了ZigBee物理层和MAC层的关键技术,并在ZigBee协议帧结构的基础上,设计了EPA与ZigBee通讯协议模型和ZigBee MAC层协议的通讯协议帧模型,给出了接入到EPA架构下控制网络的实现方案;在ARM9200的嵌入式系统控制下,通过对ZigBee接入节点装置的软硬件设计,实现了基于EPA标准的ZigBee网络的接入;经分析测试,ZigBee接入节点装置可稳定运行,适用于多种工作现场。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.